Summary form

Small Explorer and Missions of Opportunity
Investigation Summary Form

AO 97-OSS-03

Small Explorer Program and Missions of Opportunity

Principal Investigator Professor Robert P. Lin
Department Space Sciences Laboratory
Company/Institution University of California, Berkeley
Street Address Centennial Drive at Grizzly Peak Blvd.		City/Town Berkeley
State California	Zip/Postal 94720-7450	Country USA
Telephone (510)642-1149	Fax (510)643-8302	E-Mail Address rlin@sunspot.ssl.berkeley.edu

Proposal Title

The High Energy Solar Spectroscopic Imager (HESSI)

Science Theme Supported (1 = primary; 2 = secondary)
[ ] Structure and Evolution of the Universe
[ 1] The Sun-Earth Connection
[ ] Astronomical Search for Origins and Planetary Systems

Abstract (Limit 150 words)

HESSI will investigate the physics of particle acceleration and energy release in solar flares. Observations will be made of X-rays and gamma rays from 3 keV to 20 MeV with an unprecedented combination of high resolution imaging and spectroscopy. HESSI uses Fourier-transform imaging with 9 bi-grid modulation collimators and cooled germanium detectors mounted on a Sun-pointed spin-stabilized spacecraft in a low-altitude orbit with an inclination of 38º. It will provide the first imaging spectroscopy in hard X-rays with ~2 arcsecond angular resolution, time resolution to tens of ms, and ~1 keV energy resolution; the first gamma-ray line spectroscopy with ~2-5 keV energy resolution; and the first gamma-ray line and continuum imaging with ~36-arcsecond angular resolution. HESSI is planned for launch by July 2000, in time to detect the thousands of flares expected during the next solar maximum.

Mission Mode (Check one)
[X]Small Explorer
[ ]Mission of Opportunity

Cost (FY97$)
NASA Mission Cost $66.7million
Total Mission Cost $72.2 million

Anticipated Launch Vehicle:
SELVS-II, Payload Envelope A

Co-Investigator(s) at Other Institutions

Dr. Brian R. Dennis
NASA Goddard Space Flight Center
Brian.R.Dennis.1@gsfc.nasa.gov

Dr. Carol Jo Crannell
NASA Goddard Space Flight Center
Carol.J.Crannell.1@gsfc.nasa.gov

Dr. Gordon D. Holman
NASA Goddard Space Flight Center
Gordon.D.Holman.1@gsfc.nasa.gov

Dr. Reuven R. Ramaty
NASA Goddard Space Flight Center
Reuven.R.Ramaty.1@gsfc.nasa.gov

Dr. Tycho T. von Rosenvinge
NASA Goddard Space Flight Center
tycho@lheamail.gsfc.nasa.gov

Prof. Richard C. Canfield
Montana State University
canfield@isass6.solar.isas.ac.jp

Prof. A. Gordon Emslie
University of Alabama in Huntsville
emslieg@email.uah.edu

Dr. Hugh S. Hudson
Solar Physics Research Corporation
hhudson@solar.stanford.edu

Dr. Gordon J. Hurford
California Institute of Technology
gh@sundog.caltech.edu

Mr. Norman W. Madden
Lawrence Berkeley National Laboratory

Prof. H. Frank van Beek
Delft University of Technology, The Netherlands
fvanbeek@worldaccess.nl

Co-Investigators not funded by NASA:

Prof. Arnold Benz
Institute of Astronomy ETHZ, Switzerland
abenz@solar.stanford.edu

Dr. Patricia L. Bornmann
National Oceanic and Atmospheric Administration
pbornmann@solar.stanford.edu

Prof. John C. Brown
University of Glasgow, Scotland, UK
john@astro.gla.ac.uk

Dr. Shinzo Enome
National Astronomical Observatory, Japan
enome@hotaka.mtk.nao.ac.jp

Dr. Takeo Kosugi
National Astronomical Observatory, Japan
kosugi@laputa.mtk.nao.ac.jp

Dr. Nicole Vilmer
Observatoire de Paris-Meudon, France
vilmer@obspm.fr

Dr. Alex Zehnder
Paul Scherrer Institut, Switzerland
Alex.Zehnder@psi.ch